Homologous Loci in Wild and Cultivated American Cottons

Abstract

ON cytological grounds1, the New World cultivated cottons are thought to be allopolyploids with two genoms each of thirteen chromosomes derived from species cytologically homologous with the present Asiatic arboreum-herbaceum group of species and with the North American thirteen chromosome species (aridum, Armourianum and trilobum). Genetical confirmation of the part played by the present cultivated Asiatic cottons or their ancestors in the origin of the New World cultivated group, was later provided by my demonstration2 that a gene could be transferred from an Asiatic to a New World cotton by repeated back-crossing.